The present invention relates to a semiconductor laser device and a method for producing the same.
FIG. 8A is a schematic top plan view of a conventional semiconductor laser device, and FIG. 8B is an equivalent circuit diagram of the semiconductor laser device of FIG. 8A. The conventional semiconductor laser device has, as shown in FIG. 8A, a semiconductor laser element 81, a photodetector 82, and a package 83 housing them, the components being mounted onto a wiring board 84. The wiring board 84 has a wiring pattern 85, and capacitors 86 for suppressing power source noise are arranged on the wiring pattern 85. Further, fixation of the capacitors 86 is performed with the use of soldering and so on.
As shown in FIG. 8B, in the semiconductor laser device with the above constitution, a power source device 101 outside of the package 83 supplies electric energy to the photodetector 82 through wirings of the wiring pattern 85. At this time, the capacitors 86 suppress noise from the power source device 101 from being amplified by an internal circuit of the photodetector 82 so much that the amplified noise would appear as oscillation in an output signal of the photodetector 82. That is, an increase in the oscillation level of the light-emitting element 82 is suppressed by the capacitors 86.
However, since the capacitors 86 are disposed outside of the package 83, the distance between the photodetector 82 and the capacitors 86 is as long as 10 mm-20 mm, resulting in a problem in that the power source noise suppression effect is reduced or attenuated.
Further, it is required to provide the wiring board 84 with a space for the capacitors 86, and thus there is a problem that the wiring pattern 85 has little freedom of design.